Removal of wool from animal skins



Patented June 25, I I 1 w 1 w I UNITED STATES PATENT OFFICE] Wolf Kritchevsky, Chicago, 111.

No Drawing. Application December 3, 1934, Serial No. 755,773

12 Claims. (CI. 92-10) My invention relates to the recovery of fur and of scrap skins, the skins being boiledin the soluhair from skins of animalsparticularly the retion for a short time, or between one-half and covery of Wool from scraps of skeepskin. one hour or thereabouts, until the wool or hair In the fur trades, scraps of sheepskin are obportion a a s from the skin and the skin 5 tained in different manufacturing and tailoring is Substantially entirely dissolved- All this time 5 processes and this wool, if not recovered, reprethe acid liquor is run ofi and the resulting wool, sents a considerable economical loss. It is known after Washing, is found to be of a very light color, that wool can be removed from sheepskin by differing markedly from the wool recovered when digesting the skin with a dilute solution'oi sulsulphuric acid is used, principally in being of a phuric acid, thereby liberating the wool which can lighter 801011 thereafter be treated in various ways. This proc- While 'fl preferred Practice Of the i ness, however, is applicable to only a relatively t using O y mineral acids} S small proportion of cases. When the skin has White metal scraps are a d the i b not been tanned at all, or when it has been alumithis step 0 feature i 1101? Essential ,Wlln' p n'um tanned, the simple dilute sulphuric acid 'p ic c i s I h e un at n s me 15 processis fairly satisfactory. On all other tanned a es he se of scrap metal in theacidlbath' isof skins, such as chrome and bark tanned skins, the some value as it has a reducing action, and the simple sulphuric acid treatment heretofore wool recovered is sometimes of a somewhatlightknown inthe art will produce a wool having a 0 dark reddish brown shade, Such a'wool. is al- The wool now recovered may be further treated most valueless except for inferior grades of fabwith a solution of avery m alkali l lin rics, for example, which may be left undyed or p u to Which a reducing agent s' e dyed very dark colors. While I can use an alkali wash followed by a re- By my process, I treat chrome and bark tanned ducing treatment as 'describedin my prior applie,

sheepskin and sheepskin scraps to recover a wool a 1y gOOd results the use O a g e that is practically white and can be used in the a AS an sXrlmple, W001 is s p same Way that ordinary grades of wool are used about four 0 five ou a Solution O /i% in spinning, weaving and the like, and can be of borax, o soap, and or sodium hy -Q dyed any desirable shade Without difficulty. sulphite until the 0 has turned to a tan or ry 'In my priorco-pending application, Seri l N color. At this time, it-is removed, washed and 0 724,392, filed-May 1, 1934, I describe a process d The yield by h pr s s a ut ty. for treating chrome and bark'tanned sheepskin pounds of W001 fromv One hundred- POllIlds 0f scraps and the like by the use of a mineral acid, W D- i 1 t y employing certain features of a novel nature. InSfieadOf treating w 01w t t ea ka1in While the process of my prior application in-, and reducing bathlt ay be treated directly wi h. volved the use of any mineral acid,'it was dea reducing agent, and a greatly impr ved and scribed and had its principal advantage in con- Commercial product producedp nection with the use of sulphuric acid. I have the w 1 taken i thecarbonizins h s now found that if I employ phosphoric acid inp ed na /4% to 1% solution of hydros p stead of sulphuric acid, or other mineral acids, 1 a S m v reducing bath, n Stirred-fora Short very remarkable and unexpected results are obtime up to several hours at luke warm or hot tem v tained, and some of the features required in the peratures. The product produced by'this treat'- practice of the invention described in my prior. ment is practically colorless. The same or simiapplication are not so essential. The manner in lar results'cannot be obtained when employing,

which the use oi phosphoric acid improves the sulphuric acid. I, v,

process and the respects in which features of my Insteadof Y using a separate .reducingfbathg'l, prior invention are either modified or deleted may add the reducing agent directly to'thecar entirely will be apparent from a consideration bonizing bath. This modification is not =,pre-

of the following description. ferred, however, because too much reducing agent I first prepare a solution of phosphoric acid as a rule is required. 50 by adding to one hundred gallons of water, one- Still another possibility is to wash the carbonhalf to two gallons of phosphoric acid of 50% ized product in an alkaline bath, as inmany cases strength, it being understood that more or less the scraps carbonized with phosphoric acid are acid will be added depending upon its strength. sufficiently light in color so that areducing bath To this acid solution is added one hundred pounds is not necessary. In this case, a very dilute 55 alkaline solution is required, such as a solution with or without a buffer, such as soap. The wool may be merely rinsed in the alkaline bath, or it may be heated for some little time. In many cases, commercially satisfactory products are produced by such simple means. In general, I prefer to use an alkaline reducing bath after carbonizing, as uniform and perfect results are then assured.

The advantages to be secured by the use of phosphoric acid in my present processare believed fairly obvious to those skilled in the art. :By,

using phosphoric acid as acarbonizing agent, very little color, is transferred to the hair and wool, and so the hair and wool instead of coming out a dark red color after carboni'zing is a very light, slightly orange brown or pinkish 6010.1. .Which inv itself is a.

commercial product. In other words, this product may be washed and soldas a commercial product without further treatment. The 'wolol' obtained by the carbonizing step-of my present process may be subsequentlytreated by an alkaline and reducing wash, and the washing can be done at a lower temperature than when sulphuric acid" carbonization is used, and much more pleasing results will be obtained. Then again, a reducing step may be-used after carbonization,

-without the use of an alkaline wash. Another advantage of the present process is that a greater yield of wool is obtained with a given amount of scrap Furthermore, since a lower'temperature can be used in the alkaline wash, there is much less danger of gelatinizing the wool and in general the use of a buffer is not necessary.

My invention is described as taking place in a T number of, steps, but thoseskilled in the art understand that in the practicalcarrying on of the process, continuous operations may be used; In other words; the process lends itself to either batch or continuous treatment, depending upon the scraps. Although the invention is of principal value in the treatment of scraps of sheepskin, it is not limited to this specific use. The term wool is used in the claims, therefore, to include any hair, fur, or woollike substance growing out of animal skin.

Although the specification sets out exact percentages and amounts of specific materials employed in the process, particularly in the examples, it is to be understood that modifications may be made and a process employed coming within the scope of the appended claims. 7 For example, the amount of phosphoric acid used may be modified to take care of changed conditions. Where sodium salts are called for, other alkali salts of the same and similar substances may be substireacting substance.

skin with a solution of the skin, and thereafter treating the wool with a.

way of limitation, but are given for the purpose of illustration and example.

What I claim as new and desire to protect by Letters Patent of the United States is:

l. The method of recovering wool from dyed animal skin, which includes the step of boiling the skin in a dilute solution of phosphoric acid.

2. The method of recovering wool from dyed animal skin, which includes the step of boiling the skin in a dilute solution of phosphoric acid to which a non-ferrous metalv in relatively finely divided form has been added.

' 3. The method of recovering wool from animal skinwhich includesthe step of treating the skin with a phosphoric acid solution to free the wool from the skin, and thereafter treating the wool with a dilute solution of an alkaline substance. Y 4. The method of recovering wool from animal skin, including the step of treating the skin with a solution of phosphoric acid to free the wool from the skin, and thereafter treating the wool with a dilute solution of an alkaline substance and reducing agent. 7 I s 5. The method of recovering wool from dyed animal skin, which includes the step of treating the skin with a dilute solution of phosphoric acid. 6; The method of recovering wool from dyed animal skin, which includes the step of treating the skin with a dilute solution of phosphoric acid to which'a non-ferrous metal in relatively finely in a phosphoric acid solution to free'the wool from the skin, and thereafter treating the wool with a dilute solution of analkaline substance.

8. The method of recovering wool from animal skin, including the step of boiling the skin in a solution of phosphoric acid to free the wool from the skin, and thereafter treating the wool with a dilute solution of an alkaline substance and reducing agent.

9. The method of recovering wool from dyed animal skin which includes the step of treating the skin with a dilute solution of phosphoric acid to free thewool from the skin, and thereafter treating the wool with a solution of an alkaline 10. The method of recovering wool from dyed animal skin which includesthe step of treating the skin with a dilutesolution of phosphoric acid to free the wool from the skin, and thereafter treating the wool with a solution of an alkaline reacting substance and a reducing agent.

ll. The method of recovering wool from animal skin which includes the step of treating the phosphoric acid to free the wool from the skin, and thereafter treating the wool with a dilute solution of approximately borax, soap and sodium hydrosulphite.

12. The method of recovering wool from animal skin,'which includes treating the skin with a solution of phosphoric acid to free the wool from reducing agent.

WOLF KRITCHEVSKY. 

